The present invention relates to a golf club having a specific combination of a reverse flex of the golf club and a thickness distribution of the face portion of a hollow golf club head capable of controlling decrease in the rebound performance on off-center hit.
In recent years, a hollow golf club head having a face portion comprising a central thick part and a thin part therearound has been proposed for example as disclosed in U.S. Patent Application Publication U.S.-2010-105501-A1.
In such a golf club head, owing to the thin surrounding part, it is possible to control the decrease in the rebound of the golf ball on off-center hit.
By the way, due to the structure of the golf club (a), the center G of gravity of the club head (b) is positioned at a certain distance from the center line (d) of the shaft (c). Accordingly, during down swing, due to the centrifugal force, the club head (b) moves closer to the swing plane. As a result, as shown in FIG. 10, the shaft (c) is bent, and the toe b1 of the club head (b) comes down (toward the ground) when compared with the position at address. Thus, so called toe-down is caused. With increase in the toe-down, the golf ball hitting positions vary wide in the toe-heel direction of the club face.
The present inventor, therefore, studied on the toe-down during down swing quantitatively in relation to the reverse flex of the club, and discovered that the decrease in the rebound performance on off-center hit can be minimized by specifically defining the thickness distribution of the face portion based on the reverse flex.